I'm surprised neither your oil supplier nor your pump supplier had the answer here. It's a fairly well known process called mechanodegradation. The high shear rate that the hydraulic system imposes on the oil causes some of the heaviest [largest/longest chain] hydrocarbon molecules to be...
Not being able to break into the manifold makes it tricky. Can you send a circuit? Here's a few suggestions anyway, hopefully one of them has some potential.
If the actuator always works at the same sort of pressure (when running properly) then you could consider teeing a small, rapid response...
On systems with multiple LS signals where several actuators have to operate simultaneously it is common practice to install pressure compensated flow control valves for each service. The actuator which is working at the highest pressure “calls the tune” and dictates what the pump pressure will...
Hi there Hydroman247
If your rotary actuator is receiving its flow from a simple throttle valve then the only reason you are over-speeding sometimes is because there is too much pressure drop across the valve, i.e., you are getting too much flow. Your load sensing system is supposed to be...
Sorry, I was away for the weekend and didn't pick up on your request for details of the pump I suggested - anyway, you seem to have found a suitable candidate.
With a centrifugal pump you will have maximum flow rate at minimum head (outlet pressure) and zero flow rate at maximum head (the point...
Decades ago I worked on a project which entailed close liaison with a well renowned firm of consulting civil engineers. One of the consultants sort of took me under his wing and gave me an excellent piece of advice: Any fool can build a bridge which stays up, but it takes an expert to build a...
The Davey pump looks like a good enough choice to me. So what if the guy was reading the datasheet out to you - would you prefer him to have memorised it, or made up the numbers?
A petrol pump is going to be a bit of a pain to start and stop automatically (you will need a float switch and an...
I only mentioned the ROV application as an example where the physical effect of a general increase in absolute pressure causes a general increase of bulk fluid viscosity.
Jesahe's original question was all about the Fanning equation indicating that the absolute pressure was not a consideration...
Mineral oils certainly do exhibit a significant change of viscosity with pressure.
The Barus equation gives this relationship as:
VP = Vatm * e^(alpha * P)
Where “Vp” is the absolute viscosity at the new pressure, “Vatm” is the absolute viscosity at atmospheric pressure, “P” is the new...
I can see why you would want a pressure compensated flow control valve now – presumably you want the speed to remain constant regardless of the force needed to push the sample. You might, however, be disappointed with the performance of the simple pressure compensated flow control valves which...
Hi Mike
The thing looks like a press of some sort. It is possible that using the existing relief valve as a bypass flow control will prevent the cylinder from acheiving the full application force.
DOL
There are a lot of systems that do use accumulators as a suspension spring (fork lift trucks being a common example). It is also common to switch an accumulator into circuit on the lift circuits of off road boom lift vehicles.
The business of the gas heating up when it is compressed (during...
Well there's the answer!
Your pump flow rate is 60 cubic inches per minute - that's less than 0.26 USGPM. Your flow control valve is actually a 3/8" NPTF pressure compensated flow control valve with reverse flow check and a quick check of the valve's datasheet shows that the MINIMUM setting of...
I’m surprised that you are limiting your deliberations to such a narrow temperature band. You haven’t said where in the world you will be running this vehicle so let’s guess at somewhere in the temperate zones of the northern hemisphere. It is easy to imagine that, after running at high speed...
